The Mixed Alloyed Chemical Composition of Chloro-(chloro)_n-Boron Subnaphthalocyanines Dictates Their Performance as Electron-Donating and Hole-Transporting Materials in Organic Photovoltaics

Abstract

Chloro(chloro) n boron subnaphthalocyanine (Cl−Cl n BsubNc) from a commercial source and two synthetic routes were each tested as electron-donating and holetransporting materials in planar as well as bulk heterojunction (PHJ and BHJ) organic photovoltaic (OPV) devices. We have previously reported that each Cl−Cl n BsubNc sample is a mixed alloyed composition, wherein each has a varying degree of bay-position chlorination. We have determined that increasing bay chlorination has a beneficial effect on the fill factor of PHJs. Comparison between this new and our past OPV data sets, which utilized the same set of Cl−Cl n BsubNcs as electron acceptors and transporters, reveals that the increase of fill factor and performance is likely due to improved exciton transport and higher levels of bay-position chlorination. While we identify two possible mechanisms for this, further studies will be required to determine whether the phenomenon is driven by decreased radiative relaxation or due to enhanced thermal hopping from a narrower density of states. We conclude that the usage of Cl−Cl n BsubNc with higher levels of bay-position chlorination, achieved through the "nitrobenzene process," is likely to result in higher-performance OPVs.

Recent advances in subphthalocyanines and related subporphyrinoids

“…Regarding SubPcs with different peripheral substitution, in 2018, the potential of 224 as alternative donor material was explored. 375 As will be commented in Section 4.1, 224 is synthetized in combination with alloyed mixtures of Cl-SubNcs which have at least one chlorine atom in the bay position. Thus, Bender et al assessed the impact of the different degree of chlorination on the performance of SubNc in a ITO/PEDOT:PSS/H 18Àn Cl n SubNc-Cl/ C 70 /BCP/Ag configuration.…”

Updated Calibrated Model for the Prediction of Molecular Frontier Orbital Energies and Its Application to Boron Subphthalocyanines

“…21,22 As an example, BsubPcs have been shown to have particular interest due to their use in a reasonable efficient OSC as affordable materials and their unusual versatility, being able to function as either of the two necessary active layers and replace fullerenes as electron acceptors in OSCs. 23,24 The Pc and BsubPc family of semiconductors has been shown to be well suited for HOMO/LUMO energy tuning. The number of possible materials and therefore possible HOMO/LUMO energies grow exponentially as each of the following synthetic factors is considered: incorporation of different core metals or metalloids, functionalization of the metal or metalloid (the axial position), functionalization of the macrocycle (the periphery), and the recently reported possibility of alloying of these materials.…”

“…In a world that needs sustainable materials, Pcs and BsubPcs are suitable, as their synthesis is simple , and they have a low embedded energy and long-term stability under operating conditions. , As an example, BsubPcs have been shown to have particular interest due to their use in a reasonable efficient OSC as affordable materials and their unusual versatility, being able to function as either of the two necessary active layers and replace fullerenes as electron acceptors in OSCs. , …”

Exploring the Effects of Bay Position Chlorination on the Emissive Properties of Chloro-(Chloro)n-Boron Subnaphthalocyanines for Light Emission.

“…Boron subnaphthalocyanines (BsubNcs, Figure 1) are a subgroup of the phthalocyanine macrocyclic family, which have attracted interest as functional organic semiconductors [1][2][3][4] and sensor materials [5] because of their synthetic tunability [6][7][8][9] and high thermal, chemical and photo-stability. [10][11][12] Structurally BsubNcs, and their counterparts boron subphthalocyanine (BsubPc), [13] differ from conventional metal-and metalloid-phthalocyanines (MPcs) [14] because of their molecular non-planar conformation and reduced trimeric ligand structure.…”

“…[2] A similar trend was shown when Cl-ClnBsubNcs where applied as electron donating materials. [4] It has also been shown that mixed alloyed composition remains constant on further chemical derivatization of Cl-ClnBsubNc and enables their integration into bulk-heterojunction OPVs. [9] In contrast with the developments in OPVs, far fewer reports exist on the applications of BsubPcs showing a mixture of host (Alq3) and guest emission, with a peak EQE 0.41% .…”